Disclaimer

  • References: Nigeria Centre for Disease control (NCDC), see here:

Nigeria Center for Disease Control and Prevention

Nigeria Center for Disease Control and Prevention
  • More information: for a dynamic report of the 🇳🇬 Lassa fever situation in Nigeria , go to 🔗

Lassa fever in Nigeria - data from 2020 to 2024

The overall burden of Lassa fever in Nigeria

  • Nigeria has the highest burden of Lassa fever cases in West Africa.
  • Strengthening of capacity for lab diagnostics and case management in previous years resulted in greater case detection.
  • Major LF outbreaks reported in since 2018, with 5344 confirmed cases since 2020.

The effect of seasonality on the Lassa fever incidence

  • Lassa fever cases in Nigeria by week show a seasonal effect: the number of cases peaks during the dry season period (from epi week 47 - week 12).
  • The seasonal increase of cases during the dry period may be attributed to an increase of the infected rodent population and/or a seasonal behavioural change in the human population resulting in a higher risk of exposure to infected animals and/or to food/household items contaminated with rodent excreta.

  • Lassa fever cases in Nigeria by week show a seasonal effect: the number of cases peaks during the dry season period (from epi week 47 - week 12).
  • The seasonal increase of cases during the dry period may be attributed to an increase of the infected rodent population and/or a seasonal behavioural change in the human population resulting in a higher risk of exposure to infected animals and/or to food/household items contaminated with rodent excreta.

Lassa fever in Nigeria: where do efforts need to focus?

From January 2018 to December 2024, 75% of Lassa fever confirmed cases were from Ondo (33%), Edo (31%) and Bauchi (11%).

  • Total suspected cases: 42,994
  • Total confirmed cases: 6,193
  • Deaths from Confirmed Cases: 1,135
  • Case Fatality Ratio: 21%
  • Number of Health Care Workers: 235

Lassa fever suspected cases, confirmed cases and CFR by State, Nigeria 2020-2024

Lassa fever by State, Nigeria 2020-2024: Interactive maps

Suspected cases of Lassa fever

  • From 2017-2024, a total of 36,022 suspected cases were reported from 26 in Zamfara to 13,950 in Edo.

Case fatality rate (CFR) among confirmed Lassa fever cases

  • From 2017-2024, CFR among all lab confirmed cases in Nigeria was between 16-27% and decreased over time.
  • In 2024, overall CFR for Nigeria was 16% and differed greatly by individual State.
  • The variation in CFR is likely due to late patient presentation and differences in case management, highlighting the need for improvement.

Lassa fever infections among healthcare workers

  • From 2020-2024, a total of 212 healthcare workers (HCW) were reported among confirmed cases, that is 4% of Lassa fever cases.
  • From 2020-2024, 60% of all HCW infections were from Ondo (26%), Bauchi (20%), Edo (15%) States where 75% of all Lassa fever patients were being cared for. 12% of HCW infections are reported from Ebonyi where 6% of Lassa fever patients were being cared for.
  • Higher proportion of HCW in States with low incidence (10-30%).

Lassa fever in 2025 - Data from epi-week 1 to epi-week 32

Suspected cases of Lassa fever in 2025

  • In 2025, a total of 6,972 suspected cases were reported from 1 in Kebbi, Sokoto, Zamfara to 2,280 in Edo.

Cumulative number of confirmed Lassa fever cases in 2025

  • Nigeria has the highest burden of Lassa fever cases in West Africa.
  • Strengthening of capacity for lab diagnostics and case management in previous years resulted in greater case detection.
  • Major LF outbreaks reported in since 2018, with 5344 confirmed cases since 2020.

Seasonality of Lassa fever

  • In 2025, similar trend as per previous years confirming a seasonal effect on Lassa fever incidence.
  • Compared to 2024, 10% decrease in the cumulative number of suspected cases reported.

  • In 2025, similar trend as per previous years confirming a seasonal effect on Lassa fever incidence.
  • Compared to 2024, 13% decrease in the cumulative number of confirmed cases reported.

States reporting Lassa fever confirmed cases in 2025

  • In 2025, as of epi week 32, 87% of LF cases are from Ondo (33%), Bauchi (23%), Edo (17%), and Taraba (14%) States.

  • Total confirmed cases: 849

  • Deaths from Confirmed Cases: 159

  • Case Fatality Ratio: 19%

  • Number of Health Care Workers: 23

Lassa fever suspected cases, confirmed cases and CFR by State in 2025

Lassa fever by State, Nigeria 2025: Interactive maps

Case fatality ratio among confirmed Lassa fever cases by State in 2025

  • As of epi week 32 2025, cumulatively 849 cases and 159 deaths (CFR=19%) across 21 States have been reported.
  • At same period 2024, a total of 28 States reported at least one confirmed cases.
  • There is a 10% decrease in the number of suspected cases reported in 2025 compared to 2024.
  • There is a 13% decrease in the number of confirmed cases reported in 2025 compared to 2024.
  • In 2024,
    • 37 States had reported at least one suspected case versus 37 States in 2025 to date.
    • 28 States had reported at least one confirmed case versus 21 States in 2025 to date.

Health care worker infections 2020-2025 epiweek 32


  • Top 5 states:
    • 8 HCW infections in Ondo
    • 4 HCW infections in Bauchi
    • 3 HCW infections in Edo
    • 3 HCW infections in Taraba
    • 2 HCW infections in Gombe.

  • As of epi week 32 of 2025, there has been 23 healthcare workers infected, that is 3% of confirmed cases.

Lassa fever in most affected States - Data from 2020 to 2025 (as of epi-week 32)

Lassa fever in Ondo State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Ondo as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 2244 281 37 13%
2024 1830 262 17 6%
2023 1999 354 41 12%
2022 1160 273 50 18%
2021 490 117 38 32%
2020 853 363 65 18%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Ondo State reported 281 confirmed cases including 37 deaths (CFR 13%).
  • Compared to same period 2024, this represents:
    • 23% increase in the number of suspected cases.
    • 7% increase in the number of confirmed cases.
    • 103% increase in CFR.




  • In 2024 as of week 32:
    • 1830 in the number of suspected cases.
    • 262 in the number of confirmed cases.
    • 17 in the number of deaths.
    • 6% average CFR.




  • In 2023 as of week 32:
    • 1999 in the number of suspected cases.
    • 354 in the number of confirmed cases.
    • 41 in the number of deaths.
    • 12% average CFR.




  • In 2022 as of week 32:
    • 1160 in the number of suspected cases.
    • 273 in the number of confirmed cases.
    • 50 in the number of deaths.
    • 18% average CFR.




  • In 2021 as of week 32:
    • 490 in the number of suspected cases.
    • 117 in the number of confirmed cases.
    • 38 in the number of deaths.
    • 32% average CFR.




  • In 2020 as of week 32:
    • 853 in the number of suspected cases.
    • 363 in the number of confirmed cases.
    • 65 in the number of deaths.
    • 18% average CFR.

Lassa fever in Bauchi State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Bauchi as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 889 192 16 8%
2024 825 165 31 19%
2023 756 115 23 20%
2022 710 118 12 10%
2021 61 10 2 20%
2020 294 44 20 45%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Bauchi State reported 192 confirmed cases including 16 deaths (CFR 8%).
  • Compared to same period 2024, this represents:
    • 8% increase in the number of suspected cases.
    • 16% increase in the number of confirmed cases.
    • 56% decrease in CFR.




  • In 2024 as of week 32:
    • 825 in the number of suspected cases.
    • 165 in the number of confirmed cases.
    • 31 in the number of deaths.
    • 19% average CFR.




  • In 2023 as of week 32:
    • 756 in the number of suspected cases.
    • 115 in the number of confirmed cases.
    • 23 in the number of deaths.
    • 20% average CFR.




  • In 2022 as of week 32:
    • 710 in the number of suspected cases.
    • 118 in the number of confirmed cases.
    • 12 in the number of deaths.
    • 10% average CFR.




  • In 2021 as of week 32:
    • 61 in the number of suspected cases.
    • 10 in the number of confirmed cases.
    • 2 in the number of deaths.
    • 20% average CFR.




  • In 2020 as of week 32:
    • 294 in the number of suspected cases.
    • 44 in the number of confirmed cases.
    • 20 in the number of deaths.
    • 45% average CFR.

Lassa fever in Edo State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Edo as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 2280 147 24 16%
2024 2281 220 26 12%
2023 2566 295 36 12%
2022 2275 230 29 13%
2021 1332 158 14 9%
2020 1619 338 39 12%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Edo State reported 147 confirmed cases including 24 deaths (CFR 16%).
  • Compared to same period 2024, this represents:
    • 0% decrease in the number of suspected cases.
    • 33% decrease in the number of confirmed cases.
    • 38% increase in CFR.




  • In 2024 as of week 32:
    • 2281 in the number of suspected cases.
    • 220 in the number of confirmed cases.
    • 26 in the number of deaths.
    • 12% average CFR.




  • In 2023 as of week 32:
    • 2566 in the number of suspected cases.
    • 295 in the number of confirmed cases.
    • 36 in the number of deaths.
    • 12% average CFR.




  • In 2022 as of week 32:
    • 2275 in the number of suspected cases.
    • 230 in the number of confirmed cases.
    • 29 in the number of deaths.
    • 13% average CFR.




  • In 2021 as of week 32:
    • 1332 in the number of suspected cases.
    • 158 in the number of confirmed cases.
    • 14 in the number of deaths.
    • 9% average CFR.




  • In 2020 as of week 32:
    • 1619 in the number of suspected cases.
    • 338 in the number of confirmed cases.
    • 39 in the number of deaths.
    • 12% average CFR.

Lassa fever in Taraba State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Taraba as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 327 118 36 31%
2024 237 99 21 21%
2023 279 93 29 31%
2022 84 34 15 44%
2021 58 19 12 63%
2020 118 57 22 39%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Taraba State reported 118 confirmed cases including 36 deaths (CFR 31%).
  • Compared to same period 2024, this represents:
    • 38% increase in the number of suspected cases.
    • 19% increase in the number of confirmed cases.
    • 44% increase in CFR.




  • In 2024 as of week 32:
    • 237 in the number of suspected cases.
    • 99 in the number of confirmed cases.
    • 21 in the number of deaths.
    • 21% average CFR.




  • In 2023 as of week 32:
    • 279 in the number of suspected cases.
    • 93 in the number of confirmed cases.
    • 29 in the number of deaths.
    • 31% average CFR.




  • In 2022 as of week 32:
    • 84 in the number of suspected cases.
    • 34 in the number of confirmed cases.
    • 15 in the number of deaths.
    • 44% average CFR.




  • In 2021 as of week 32:
    • 58 in the number of suspected cases.
    • 19 in the number of confirmed cases.
    • 12 in the number of deaths.
    • 63% average CFR.




  • In 2020 as of week 32:
    • 118 in the number of suspected cases.
    • 57 in the number of confirmed cases.
    • 22 in the number of deaths.
    • 39% average CFR.

Lassa fever in Ebonyi State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Ebonyi as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 264 23 13 57%
2024 319 44 25 57%
2023 256 51 29 57%
2022 235 41 19 46%
2021 89 17 8 47%
2020 249 76 22 29%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Ebonyi State reported 23 confirmed cases including 13 deaths (CFR 57%).
  • Compared to same period 2024, this represents:
    • 17% decrease in the number of suspected cases.
    • 48% decrease in the number of confirmed cases.
    • 1% decrease in CFR.




  • In 2024 as of week 32:
    • 319 in the number of suspected cases.
    • 44 in the number of confirmed cases.
    • 25 in the number of deaths.
    • 57% average CFR.




  • In 2023 as of week 32:
    • 256 in the number of suspected cases.
    • 51 in the number of confirmed cases.
    • 29 in the number of deaths.
    • 57% average CFR.




  • In 2022 as of week 32:
    • 235 in the number of suspected cases.
    • 41 in the number of confirmed cases.
    • 19 in the number of deaths.
    • 46% average CFR.




  • In 2021 as of week 32:
    • 89 in the number of suspected cases.
    • 17 in the number of confirmed cases.
    • 8 in the number of deaths.
    • 47% average CFR.




  • In 2020 as of week 32:
    • 249 in the number of suspected cases.
    • 76 in the number of confirmed cases.
    • 22 in the number of deaths.
    • 29% average CFR.

Lassa fever in Kogi State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Kogi as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 74 15 4 27%
2024 132 32 3 9%
2023 40 11 1 9%
2022 127 48 8 17%
2021 8 2 0 0%
2020 95 38 8 21%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Kogi State reported 15 confirmed cases including 4 deaths (CFR 27%).
  • Compared to same period 2024, this represents:
    • 44% decrease in the number of suspected cases.
    • 53% decrease in the number of confirmed cases.
    • 184% increase in CFR.




  • In 2024 as of week 32:
    • 132 in the number of suspected cases.
    • 32 in the number of confirmed cases.
    • 3 in the number of deaths.
    • 9% average CFR.




  • In 2023 as of week 32:
    • 40 in the number of suspected cases.
    • 11 in the number of confirmed cases.
    • 1 in the number of deaths.
    • 9% average CFR.




  • In 2022 as of week 32:
    • 127 in the number of suspected cases.
    • 48 in the number of confirmed cases.
    • 8 in the number of deaths.
    • 17% average CFR.




  • In 2021 as of week 32:
    • 8 in the number of suspected cases.
    • 2 in the number of confirmed cases.
    • 0 in the number of deaths.
    • 0% average CFR.




  • In 2020 as of week 32:
    • 95 in the number of suspected cases.
    • 38 in the number of confirmed cases.
    • 8 in the number of deaths.
    • 21% average CFR.

Lassa fever in Gombe State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Gombe as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 89 14 7 50%
2024 31 4 2 50%
2023 51 9 2 22%
2022 193 24 8 33%
2021 8 0 0 –
2020 37 9 2 22%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Gombe State reported 14 confirmed cases including 7 deaths (CFR 50%).
  • Compared to same period 2024, this represents:
    • 187% increase in the number of suspected cases.
    • 250% increase in the number of confirmed cases.
    • 0% decrease in CFR.




  • In 2024 as of week 32:
    • 31 in the number of suspected cases.
    • 4 in the number of confirmed cases.
    • 2 in the number of deaths.
    • 50% average CFR.




  • In 2023 as of week 32:
    • 51 in the number of suspected cases.
    • 9 in the number of confirmed cases.
    • 2 in the number of deaths.
    • 22% average CFR.




  • In 2022 as of week 32:
    • 193 in the number of suspected cases.
    • 24 in the number of confirmed cases.
    • 8 in the number of deaths.
    • 33% average CFR.




  • In 2021 as of week 32:
    • 8 in the number of suspected cases.
    • 0 in the number of confirmed cases.
    • 0 in the number of deaths.
    • NA average CFR.




  • In 2020 as of week 32:
    • 37 in the number of suspected cases.
    • 9 in the number of confirmed cases.
    • 2 in the number of deaths.
    • 22% average CFR.

Lassa fever in Benue State, 2020-2025

  • Below is an overview of Lassa fever suspected cases, confirmed cases, deaths and average CFR in Benue as of week 32:
Years Suspected cases Confirmed cases Deaths CFR
2025 155 14 5 36%
2024 1062 63 11 17%
2023 183 38 4 11%
2022 227 35 8 23%
2021 21 6 0 0%
2020 42 9 4 44%
Source: NCDC
  • See other tabs for yearly data




  • In 2025 only, Benue State reported 14 confirmed cases including 5 deaths (CFR 36%).
  • Compared to same period 2024, this represents:
    • 85% decrease in the number of suspected cases.
    • 78% decrease in the number of confirmed cases.
    • 105% increase in CFR.




  • In 2024 as of week 32:
    • 1062 in the number of suspected cases.
    • 63 in the number of confirmed cases.
    • 11 in the number of deaths.
    • 17% average CFR.




  • In 2023 as of week 32:
    • 183 in the number of suspected cases.
    • 38 in the number of confirmed cases.
    • 4 in the number of deaths.
    • 11% average CFR.




  • In 2022 as of week 32:
    • 227 in the number of suspected cases.
    • 35 in the number of confirmed cases.
    • 8 in the number of deaths.
    • 23% average CFR.




  • In 2021 as of week 32:
    • 21 in the number of suspected cases.
    • 6 in the number of confirmed cases.
    • 0 in the number of deaths.
    • 0% average CFR.




  • In 2020 as of week 32:
    • 42 in the number of suspected cases.
    • 9 in the number of confirmed cases.
    • 4 in the number of deaths.
    • 44% average CFR.

Thank you

Any questions or suggestions? Contact us: Anaïs Legand and Antoine Chaillon